Abstract
A new class of abelian -groups is introduced, the countably totally projective groups, that contains the well-known class of totally projective groups. A countably totally projective group is shown to have the property that every fully inert subgroup is commensurable with a fully invariant subgroup. This generalizes results of Goldsmith, Salce and Zanardo (2014), who proved that a direct sum of cyclic -groups has this property. It also answers affirmatively two questions recently posed in the literature.
Citation
Patrick W. Keef. "Countably totally projective Abelian -groups have minimal full inertia." J. Commut. Algebra 14 (3) 427 - 442, Fall 2022. https://doi.org/10.1216/jca.2022.14.427
Information